PCI: return error on failure to read PCI ROMs

This patch makes the ROM reading code return an error to user space if
the size of the ROM read is equal to 0.

The patch also emits a warnings if the contents of the ROM are invalid,
and documents the effects of the "enable" file on ROM reading.

Signed-off-by: Timothy S. Nelson <wayland@wayland.id.au>
Acked-by: Alex Villacis-Lasso <a_villacis@palosanto.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt
index 68ef48839c0484db0dea98da2b419eb4f94b28bf..9f8740ca3f3bc514d9f5426168eb5b2273b96d42 100644 (file)
--- a/Documentation/filesystems/sysfs-pci.txt
+++ b/Documentation/filesystems/sysfs-pci.txt
@@ -9,6 +9,7 @@ that support it.  For example, a given bus might look like this:
      |   |-- class
      |   |-- config
      |   |-- device
+     |   |-- enable
      |   |-- irq
      |   |-- local_cpus
      |   |-- resource
@@ -32,6 +33,7 @@ files, each with their own function.
        class              PCI class (ascii, ro)
        config             PCI config space (binary, rw)
        device             PCI device (ascii, ro)
+       enable             Whether the device is enabled (ascii, rw)
        irq                IRQ number (ascii, ro)
        local_cpus         nearby CPU mask (cpumask, ro)
        resource                   PCI resource host addresses (ascii, ro)
@@ -57,10 +59,19 @@ used to do actual device programming from userspace.  Note that some platforms
 don't support mmapping of certain resources, so be sure to check the return
 value from any attempted mmap.
 
+The 'enable' file provides a counter that indicates how many times the device 
+has been enabled.  If the 'enable' file currently returns '4', and a '1' is
+echoed into it, it will then return '5'.  Echoing a '0' into it will decrease
+the count.  Even when it returns to 0, though, some of the initialisation
+may not be reversed.  
+
 The 'rom' file is special in that it provides read-only access to the device's
 ROM file, if available.  It's disabled by default, however, so applications
 should write the string "1" to the file to enable it before attempting a read
-call, and disable it following the access by writing "0" to the file.
+call, and disable it following the access by writing "0" to the file.  Note
+that the device must be enabled for a rom read to return data succesfully.
+In the event a driver is not bound to the device, it can be enabled using the
+'enable' file, documented above.
 
 Accessing legacy resources through sysfs
 ----------------------------------------

diff --git a/arch/ia64/sn/kernel/io_acpi_init.c b/arch/ia64/sn/kernel/io_acpi_init.c
index c5a214026a775c5d82e27fddd1c85cad2d883598..d0223abbbbd4c464df26e0aed6823de0b827944f 100644 (file)
--- a/arch/ia64/sn/kernel/io_acpi_init.c
+++ b/arch/ia64/sn/kernel/io_acpi_init.c
@@ -443,7 +443,7 @@ sn_acpi_slot_fixup(struct pci_dev *dev)
                size = pci_resource_len(dev, PCI_ROM_RESOURCE);
                addr = ioremap(pcidev_info->pdi_pio_mapped_addr[PCI_ROM_RESOURCE],
                               size);
-               image_size = pci_get_rom_size(addr, size);
+               image_size = pci_get_rom_size(dev, addr, size);
                dev->resource[PCI_ROM_RESOURCE].start = (unsigned long) addr;
                dev->resource[PCI_ROM_RESOURCE].end =
                                        (unsigned long) addr + image_size - 1;

diff --git a/arch/ia64/sn/kernel/io_init.c b/arch/ia64/sn/kernel/io_init.c
index 4e1801bad83a7fdc171a90af0ff3c2df4277f62f..e2eb2da60f963ee3aa7e62c727ef408026b4cd13 100644 (file)
--- a/arch/ia64/sn/kernel/io_init.c
+++ b/arch/ia64/sn/kernel/io_init.c
@@ -269,7 +269,7 @@ sn_io_slot_fixup(struct pci_dev *dev)
 
                        rom = ioremap(pci_resource_start(dev, PCI_ROM_RESOURCE),
                                      size + 1);
-                       image_size = pci_get_rom_size(rom, size + 1);
+                       image_size = pci_get_rom_size(dev, rom, size + 1);
                        dev->resource[PCI_ROM_RESOURCE].end =
                                dev->resource[PCI_ROM_RESOURCE].start +
                                image_size - 1;

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index db7ec14fa7191828d91f58eb903bfc94cd60ef8c..dfc4e0ddf241b57a93c8e94d3f81a583a772074c 100644 (file)
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -768,8 +768,8 @@ pci_read_rom(struct kobject *kobj, struct bin_attribute *bin_attr,
                return -EINVAL;
        
        rom = pci_map_rom(pdev, &size); /* size starts out as PCI window size */
-       if (!rom)
-               return 0;
+       if (!rom || !size)
+               return -EIO;
                
        if (off >= size)
                count = 0;

diff --git a/drivers/pci/rom.c b/drivers/pci/rom.c
index 132a78159b60e51bc988dc17acbaec5725e0ed98..29cbe47f219f8c39f2b3f66490a272f339b1f9d5 100644 (file)
--- a/drivers/pci/rom.c
+++ b/drivers/pci/rom.c
@@ -63,7 +63,7 @@ void pci_disable_rom(struct pci_dev *pdev)
  * The PCI window size could be much larger than the
  * actual image size.
  */
-size_t pci_get_rom_size(void __iomem *rom, size_t size)
+size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom, size_t size)
 {
        void __iomem *image;
        int last_image;
@@ -72,8 +72,10 @@ size_t pci_get_rom_size(void __iomem *rom, size_t size)
        do {
                void __iomem *pds;
                /* Standard PCI ROMs start out with these bytes 55 AA */
-               if (readb(image) != 0x55)
+               if (readb(image) != 0x55) {
+                       dev_err(&pdev->dev, "Invalid ROM contents\n");
                        break;
+               }
                if (readb(image + 1) != 0xAA)
                        break;
                /* get the PCI data structure and check its signature */
@@ -159,7 +161,7 @@ void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size)
         * size is much larger than the actual size of the ROM.
         * True size is important if the ROM is going to be copied.
         */
-       *size = pci_get_rom_size(rom, *size);
+       *size = pci_get_rom_size(pdev, rom, *size);
        return rom;
 }
 

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 48890cf3f96e562937ded2fc8134f156e9fba60d..7bd624bfdcfd37945e3c59bf2a74f0d2f1dabb21 100644 (file)
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -684,7 +684,7 @@ int pci_enable_rom(struct pci_dev *pdev);
 void pci_disable_rom(struct pci_dev *pdev);
 void __iomem __must_check *pci_map_rom(struct pci_dev *pdev, size_t *size);
 void pci_unmap_rom(struct pci_dev *pdev, void __iomem *rom);
-size_t pci_get_rom_size(void __iomem *rom, size_t size);
+size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom, size_t size);
 
 /* Power management related routines */
 int pci_save_state(struct pci_dev *dev);